Masahiro Wato

Correlation of E‐and P‐cadherin expression with differentiation grade and mode of invasion in gingival carcinoma

The expression pattern of two Ca2+‐dependent cell‐cell adhesion molecules, E‐and P‐cadherin (CD), in 25 primary gingival squamous cell carcinomas (SCC) was examined immunohistochemically. The occurrence of reduced‐type expression of both E‐and P‐CD increased significantly with the grade of carcinoma differentiation, culminating in a complete loss of P‐CD in poorly differentiated SCC. The occurrence of reduced‐type P‐CD expression also increased significantly with the mode of invasion, as was the case with E‐CD. Furthermore, no P‐CD molecules were detected in one of the six SCC having a diffuse, cord‐like invasion and in three of the six having a diffuse type of invasion. These findings suggest that the down‐regulation of these cell adhesion molecules closely correlates with the differentiation grade and mode of invasion of gingival SCC.

NANOG expression correlates with differentiation, metastasis and resistance to preoperative adjuvant therapy in oral squamous cell carcinoma

NANOG protein, a transcription factor expressed in embryonic stem cells, is overexpressed in tumor development. Although studies investigating the function of NANOG in cancer have shown that it plays several roles, such as in cell proliferation, invasion and metastasis, the overall function of NANOG in cancer cells has remained elusive. In the present study, NANOG expression in oral squamous cell carcinoma (OSCC) was examined to determine its potential clinical significance. The expression of NANOG protein was assessed in 60 patients with OSCC by immunohistochemistry, and its correlation with clinicopathological factors and metastasis was evaluated. NANOG protein levels in human OSCC cell lines were determined by western blotting and immunofluorescence staining. NANOG protein expression was identified in 52 cases (86.7%) and expression levels were higher in primary foci of poorly differentiated OSCC than in those of well-differentiated OSCC, indicating that NANOG expression is associated with OSCC differentiation. Regardless of the differentiation levels of primary foci, NANOG expression levels in metastatic foci were extremely high. In addition, NANOG expression in metastatic foci was maintained at high levels following preoperative adjuvant therapy. Furthermore, NANOG protein was detected at an identical level in human OSCC cell lines. These data indicate that NANOG-expressing OSCC cells tend to metastasize and that metastatic tumors expressing NANOG may be resistant to preoperative adjuvant therapy, including chemoradiation. Thus, assessment of NANOG expression may assist the strategy for treatment of OSCC metastasis.

LOCALIZATION OF E-CADHERIN ADHESION MOLECULES IN HUMAN GINGIVA AND GINGIVAL CARCINOMA

Immunohistochemical investigations were carried out on the localization and expression of the Ca2+‐dependent intercellular adhesion molecule E‐cadherin in human gingiva and gingival carcinoma. Although E‐cadherin did not appear in the parakeratinized layer of either clinically healthy or inflamed gingiva, it did appear strongly in the prickle layer and somewhat more weakly in the basal layer. Immunogold particles reactive to anti‐E‐cadherin monoclonal antibody in the electron microscopic findings were localized only in the vicinity of the desmosomes of the prickle and basal layers.

CD56 expression is associated with neuroectodermal differentiation in ameloblastomas : an immunohistochemical evaluation in comparison with odontogenic cystic lesions

Ameloblastoma (AB), which is the most common odontogenic tumor, may originate from the dental lamina remnants. The expression of CD56, which is a transmembrane molecule, is associated with neuroectodermal differentiation of the embryonal cells. The aim of this study was to evaluate the expression of CD56 in AB, in comparison with other odontogenic cysts. We used formalin-fi xed, paraffi n-embedded specimens from 34 cases of AB, 10 cases of keratocystic odontogenic tumor (KCOT), and 7 cases of dentigerous cyst (DC). We immunohistochemically examined CD56, NeuroD1, and N-cadherin expression in these tumors as compared with the expression patterns of various epithelial markers. Seventy-four percent of AB showed immunopositivity for CD56, and both CD56 and N-cadherin were diffusely positive in the outer columnar cells of AB. The immunopositivities for NeuroD1 and N-cadherin were also observed in the outer cells of AB. None of the DC cases was positive for CD56, whereas half the cases of KCOT were positive. Because CD56 is expressed in the inner enamel epithelium of enamel organs, the outer columnar cells of AB are likely to be the differentiation phenotype of the inner enamel epithelium, which is associated with neuroectodermal differentiation. The aberrant NeuroD1 expression may induce CD56 expression in AB and KCOT.

Trimethylsilylation reaction of prostaglandin-E methyl ester with various trimethylsilylating reagents

Abstract Gas chromatographic investigation of the time course of the trimethylsilylation reaction of prostaglandin-E methyl ester (PGE-Me) with trimethylsilylimidazole-piperidine (PIP), N,O-bis(trimethylsilyl)trifluoroacetamide-PIP and other silylating reagents revealed that these reagents do not always give a single product. The reaction products were characterized by gas chromatography-mass spectrometry as the trimethylsilyl derivatives of PGA-Me, PGB-Me, PGE-Me, 9-enol-PGE-Me and 11-piperidyl-PGA-Me.

Differential expression of the epithelial mesenchymal transition factors Snail, Slug, Twist, TGF-β, and E-cadherin in ameloblastoma

Epithelial mesenchymal transition (EMT), the transition of epithelial cells into motile mesenchymal cells, plays an important role in embryogenesis, cancer invasion, and metastasis. Ameloblastomas are common epithelial odontogenic tumors, occurring exclusively in the mandible with locally invasive growth. Thirty-seven ameloblastoma cases were evaluated for the involvement of EMT by immunohistochemical staining and western blotting using antibodies against Slug, Snail, Twist, TGF-β, and E-cadherin. Double immunostaining was also performed. Slug and TGF-β were expressed in the nuclei of peripheral and stellate reticulum cells of ameloblastoma nests. Twenty cases of Snail, 36 of Slug, 8 of Twist, and 19 of TGF-β showed strong expression in tumor cells in follicular and plexiform patterns. Expression of Slug and TGF-β increased in regions where the expression of E-cadherin was reduced. EMT was found to be associated with the local invasive growth of ameloblastoma. These data suggest that reduced expression of E-cadherin and over-expression of Slug, Snail, and TGF-β induce EMT. Given that ameloblastomas are characterized by local invasiveness, EMT might be related to their development. Thus, strong expression of Slug and TGF-β and reduced expression of E-cadherin might be related to the local invasiveness of ameloblastoma.

Cyclin D1 expression is correlated with cell differentiation and cell proliferation in oral squamous cell carcinomas

The present study conducted an immunohistochemical investigation of cyclin D1 and Ki-67 expression in oral squamous cell carcinoma (SCC) to evaluate the correlations between cell differentiation, cell proliferation and metastasis, and the effect of anticancer drug medication and cyclin D1 expression. Cyclin D1 and Ki-67 were detected clearly in the nuclei of 35 SCC samples. No correlation between cyclin D1 protein expression and oral SCC differentiation was found. By contrast, the majority of metastatic foci (90%) exhibited strong cyclin D1 expression, whereas weak expression was observed in metastatic foci with pre-operative adjuvant therapy. Additionally, cyclin D1 and Ki-67 were expressed in basal to suprabasal cells of well-differentiated oral SCC, whereas cyclin D1-positive and Ki-67-negative cells were present in the highly-differentiated region, according to a double-immunostaining method. These results indicate that the expression of cyclin D1 protein plays a role in cell differentiation and cell proliferation in well-differentiated oral SCC.

SOX4 expression is closely associated with differentiation and lymph node metastasis in oral squamous cell carcinoma.

SOX4 is a member of the SOX family of transcription regulators. In recent years, SOX4 was shown to be overexpressed in cancers of various organs and related to epithelial-mesenchymal transition, which is a metastatic factor. This study was the first to investigate correlations between SOX4 expression levels and the clinicopathologic factors of oral squamous cell carcinoma (OSCC). We analyzed SOX4 expression levels in 50 patients with OSCC using immunohistochemistry. All samples expressed the SOX4 protein and elevated SOX4 expression was significantly correlated with gender, T status, and stage levels. The expression level of SOX4 in primary foci of poorly differentiated OSCC was higher than that of well differentiated OSCC, which indicated that SOX4 expression is associated with the differentiation of OSCC. However, regardless of the differentiation level in the primary focus, SOX4 expression levels were found to be very high in the metastatic focus. Furthermore, SOX4 expression in metastatic foci was significantly suppressed by neoadjuvant therapy. These results indicate that undifferentiated OSCC cells expressing SOX4 are more likely to metastasize and neoadjuvant therapy including chemoradiation therapy may have some effect in metastatic prevention.

Monoclonal Antibodies Against Gingival Components

The aim of this study was to produce and characterize monoclonal antibodies against human gingival epithelial cells and gingival fibroblasts. By using these whole cells as immunogens, we were able to generate a large number of monoclonal antibodies reacting with tissue antigens, in particular antibodies that reacted with desmosomes (MoAbs 7 and 8) and basement membrane (MoAb FB-1) antigens. MoAbs 7 and 8 produced from epithelial cells stained cell membranes of epithelium and desmosomes, respectively, as shown by light and immunoelectron microscopy. The epitopes to which MoAbs 7 and 8 were reactive were stable against various treatments; only periodate oxidation abolished the tissue reactions with MoAb 8. Extraction of gingiva with SDS or NP-40, SDS-PAGE analysis, and Western blotting showed that the MoAb 8 identified an antigen with a molecular weight of 100,000 daltons. MoAb FB-1 produced from fibroblasts immunolabeled the basement membranes. The FB-1 antigen was clearly different from any of the known ubiquitous basement membrane components, such as type IV collagen, laminin, and fibronectin. Examination of the distribution and localization of the antigen showed that it was present in the basement membrane beneath stratified squamous epithelium. FB-1 did not react with any of types I-VI collagens in ELISA, but immunoelectron microscopy showed that the antigen reacting with FB-1 was present in the lamina fibroreticularis of the basement membrane and was comprised of collagen-like fibers. These results suggest the possible existence of a new collagen other than types I-VI in the basement membrane beneath stratified squamous epithelium.

Calcifying cystic odontogenic tumor accompanied by a dentigerous cyst: A case report

A calcifying cystic odontogenic tumor (CCOT) is a proliferation of odontogenic epithelium and scattered nests of ghost cells and calcifications that may form the lining of a cyst, or present as a solid mass. It was previously described by Gorlin et al in 1962 as a calcifying odontogenic cyst. Dentigerous cysts are developmental odontogenic jaw cysts, commonly manifesting in the second and third decades of life. The present study reports an asymptomatic case in a 13-year-old boy who was referred to the outpatient clinic of the Osaka Dental University Hospital (Osaka, Japan) for additional investigation of an area of radiolucency in the lower right jaw. X-ray demonstrated a unilocular, well-circumscribed, radiolucent lesion in the mandible, which measured 30×20 mm, with radiopaque structures within it. Enucleation of the lesion with tooth extraction was performed, which histopathologically revealed features of a CCOT and a cyst. To the best of our knowledge, the occurrence of such a lesion has not been previously identified. The present study examined the significance of the case with a brief review of the literature.